Can soy milk be substitued for anytime you use milk/cream?

Unsw soy milk is a good sub. I personally prefer to use low sodium chicken stock when making mac and cheese, I think it tastes better.

I like to use the unsweetened milk alternatives, so there is no confusion of sweetness or flavors. One bad experience (son's girlfriend made soup with vanilla soymilk -- hard to adjust!) made me wary of the 'improvements.' On the other hand, I've been using a vanilla milk for pancakes, mixed in cold drinks -- where a little bit of sweetness makes sense.

Agree with the answers above, especially in terms of making sure your milk isn't so thin that it will break and become too watery in your savory cooking, which you also see happen with skim milk

For savory cooking I like to use an unsweetened, unflavored soy milk. Then there's no risk. For cream, there are some 'cream' products, but it it's not critical, I'd just use one of the thicker brands, checking the fat content. Sometimes, if I have a vanilla 'milk' I like to use it for pancakes or some of the drinks from the summer drinks contest last summer.

I've used it plenty in baking, and it works great! However, I've never tried it in savory dishes.